This invention relates to an electronic door or wall mounted key safe which allows selective access to the interior of the safe so that various categories of users can be provided key access (or access to the safe for maintenance purposes) while maintaining a high level of security against unwanted users.
Manual key safes are a well-known means of providing selective access to a key which can then be used to open a door, or be used for access to any secured device, such as electronic or manual HVAC controllers, or process controllers in industrial settings. A common application is in the real estate business where numerous agents require access to a single lock but it is not cost effective or appropriate from a security standpoint to provide all such persons keys to that lock.
Numerous key safes appear in the prior art. My own prior invention, detailed in U.S. Pat. No. 4,651,544, describes a combination electronic/manual key safe the interior of which includes a tethered, retractable key. The retractable key is held within a separate key compartment which can be accessed only by electronically or manually manipulating a solenoid activated latch. While the key safe of U.S. Pat. No. 4,651,544 represented a significant advance in key safe technology, certain problems inherent to providing wide ranging access, i.e. to various categories of users, while at the same time maintaining a completely secure system were not addressed in that invention.
In particular, my earlier invention still required the use of a "hard" key in some circumstances. By "hard" key, I mean a standard physical (as opposed to an electronic code) key which is used for access to the key safe which in my earlier invention was used by a specific category of user, or during a power failure. For this reason it is an object of the present invention to provide an electronic key safe for which no "hard" key access is necessary under any circumstances.
Specifically, it is a further object of this invention to provide such a key safe which eliminates the need for hard key access even during power failures, and without compromising the security of the system.